U.S. patent application number 10/233094 was filed with the patent office on 2003-03-13 for machine tool.
Invention is credited to Haus, Waldemar, Hoffmann, Thomas, Stengele, Gerald.
Application Number | 20030049088 10/233094 |
Document ID | / |
Family ID | 26010107 |
Filed Date | 2003-03-13 |
United States Patent
Application |
20030049088 |
Kind Code |
A1 |
Stengele, Gerald ; et
al. |
March 13, 2003 |
Machine tool
Abstract
A machine tool for at least triaxial machining of work pieces
comprises a column of the type of a casing with side walls. In an
interior space, provision is made for a work spindle which projects
into a working area and which is connected via couplers and hinges
to a driving skid that is displaceably guided on each side wall
straight in a y direction. The driving skids are displaceably
guided on two guides which are spaced from each other in the z
direction. Provided between the guides are linear motors, a first
part of which is mounted on the driving skid and a second part on
the side wall.
Inventors: |
Stengele, Gerald;
(Ludwigsburg, DE) ; Hoffmann, Thomas; (Ingersheim,
DE) ; Haus, Waldemar; (Stuttgart, DE) |
Correspondence
Address: |
MCGLEW & TUTTLE, PC
SCARBOROUGH STATION
SCARBOROUGH
NY
10510
US
|
Family ID: |
26010107 |
Appl. No.: |
10/233094 |
Filed: |
August 28, 2002 |
Current U.S.
Class: |
409/235 ;
409/201; 74/490.07 |
Current CPC
Class: |
B23Q 1/56 20130101; Y10T
74/20354 20150115; Y10T 74/20341 20150115; Y10T 409/309576
20150115; B23Q 5/28 20130101; Y10S 414/13 20130101; B23Q 1/48
20130101; Y10T 409/307672 20150115; B23Q 1/626 20130101; Y10T
74/20207 20150115 |
Class at
Publication: |
409/235 ;
74/490.07; 409/201 |
International
Class: |
B23C 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 11, 2001 |
DE |
101 44 541.5 |
Apr 10, 2002 |
EP |
02 007 979.4 |
Claims
What is claimed is:
1. A machine tool for at least triaxial machining of work pieces,
comprising a column (1) of the type of a casing, which has side
walls (2, 3), an interior space (6), and a front (7), which is open
towards a working area (9); a work spindle (12), which is disposed
substantially in the interior space (6), projecting in a z
direction into the working area (9); a driving skid (15, 16) on
each side wall (2, 3), which is displaceably guided thereon
straight in a y direction; couplers (17, 18), which are articulated
to the driving skids (15, 16) by hinges (19, 20) and which are
connected to each other by a hinge (23) and which carry the work
spindle (12); and drives for the driving skids (15, 16); wherein
the driving skids (15, 16) are displaceably guided on two guides
(27 to 30) that are spaced from each other in the z direction; and
wherein the drives are linear motors (31, 32) which are disposed
between the guides (27 to 30), a first part (33) of the linear
motors (31, 32) being mounted on the driving skid (15, 16) and a
second part (35) on the side wall (2, 3).
2. A machine tool according to claim 1, wherein the guides (27 to
30) have two guide rails (27, 28) on the side of the side wall (2,
3) that is turned towards the interior space (6) and open towards
the interior space (6); and wherein guide shoes (29, 30) are
mounted on the respective driving skid (15, 16), enclasping the
guide rails (27, 28).
3. A machine tool according to claim 2, wherein two guide shoes
(29, 30) are disposed at a distance from each other on each guide
rail (27, 28), a brake shoe (49), which is mounted on the driving
skid (15, 16), being disposed between the two guide shoes (29,
30).
4. A machine tool according to claim 1, wherein a path measuring
system (38, 39) is provided between a guide (27, 29) of each
driving skid (15, 16) and the linear motor (31, 32).
5. A machine tool according to claim 2, wherein the second parts
(35) of the linear motors (31, 32) and the guide rails (27, 28) are
screwed from the interior space (6) onto the side wall (2, 3).
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a machine tool for at least
triaxial machining of work pieces, comprising a column of the type
of a casing, which has side walls, an interior space, and a front,
which is open towards a working area; a work spindle, which is
disposed substantially in the interior space, projecting in a z
direction into the working area; a driving skid on each side wall,
which is displaceably guided thereon straight in a y direction;
couplers, which are articulated to the driving skids by hinges and
which are connected to each other by a hinge and which carry the
work spindle; and drives for the driving skids.
[0003] 2. Background Art
[0004] A machine tool of the generic type is known from U.S. Pat.
No. 6,328,510 B1, comprising a guide for a skid on the front turned
towards the working area. Further details cannot be seen from this
publication.
SUMMARY OF THE INVENTION
[0005] It is an object of the invention to embody a machine tool of
the generic type such that reliable guidance and anti-torsion
actuation are obtained, accompanied with a compact design.
[0006] According to the invention, this object is attained by the
features wherein the driving skids are displaceably guided on two
guides that are spaced from each other in the z direction; and
wherein the drives are linear motors which are disposed between the
guides, a first part of the linear motors being mounted on the
driving skid and a second part on the side wall. Arranging the
guides and the linear drives, which lie between them, on the side
of the side walls that is turned towards the interior space helps
obtain anti-torsion guidance of the driving skids and direct
transmission of the attraction powers of the linear drives onto the
skids. All in all, this leads to a very rigid structure of the
entire work spindle motion mechanism. The guides and the linear
drives are positioned for ease of accessibility and assembly and
disassembly. This is accompanied with a depth arrangement of the
guides and drives within the column.
[0007] When the guides have two guide rails on the side of the side
wall that is turned towards the interior space and open towards the
interior space, and when guide shoes are mounted on the respective
driving skid, enclasping the guide rails, this reflects an
optimized embodiment of the guides. It is possible to integrate a
safety mechanism wherein two guide shoes are disposed at a distance
from each other on each guide rail, a brake shoe, which is mounted
on the driving skid, being disposed between the two guide
shoes.
[0008] A path measuring system, which is provided between a guide
of each driving skid and the linear motor, may be integrated in the
design according to the invention.
[0009] Further features, details and advantages of the invention
will become apparent from the ensuing description of an exemplary
embodiment, taken in conjunction with the drawing.
BRIEF DESCRIPTION OF THE DRAWING
[0010] FIG. 1 is an elevation of the machine tool;
[0011] FIG. 2 is a vertical section through the machine tool on the
line II-II of FIG. 1; and
[0012] FIG. 3 is a horizontal partial section through the machine
tool on the line III-III of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0013] The machine tool seen in the drawing for the at least
triaxial machining of work pieces by a rotatably drivable tool
comprises a parallelepiped column 1, which is composed of two
vertical side walls 2, 3 parallel to each other, a bottom 4 and an
upper part 5, connecting the side walls 2, 3 with each other. The
column 1 encloses a so-called actuator space as an interior space 6
and is open at its two fronts 7, 8. A working area 9 is disposed
before the front 7, where a work piece holder 11 (only roughly
outlined) is arranged on a machine bed 10 that is joined to the
column 1.
[0014] A work spindle 12 in the form of a motor spindle is provided
in the interior space 6, projecting through the front 7 into the
working area 1 and carrying a rotatably drivable tool 13 for
machining a work piece 14 that is disposed on the work piece holder
11. Customarily, the front 7 is hidden by a cover (not shown) which
moves along with any motions of the work spindle 12 in the
horizontal x direction and the vertical y direction, which is
however no supporting member of the column 1, but only serves to
separate the working area 9 from the interior space 6. The work
spindle 12 may be movable in the z direction that is vertical of
the x-y plane; but it is just as well possible that the work piece
holder 11 is movable in the z direction in familiar manner.
[0015] For moving the work spindle 12, two driving skids 15, 16 are
provided, which are movable in the y direction and guided on the
inside of the side walls 2, 3 and connected to each other by two
couplers 17, 18. Each coupler 17, 18 is connected to the associated
skid 15, 16 by means of a hinge 19, 20 that has an axis of rotation
21, 22 running in the z direction. The two couplers 17, 18 are
again joined to each other by a hinge 23 with an axis of rotation
24 that runs in the z direction. A tubular work spindle support 25,
with the work spindle 12 therein, is mounted on one coupler 18 in
vicinity to the hinge 23. Due to the fact that the three axes of
rotation 21, 22, 24 extend in the z direction and the skids 15, 16
in the y direction, the work spindle 12, upon displacements of the
skids 15, 16, can be shifted parallel to itself in the x-y plane
within a working range 26 that lies in this plane.
[0016] The couplers 17, 18, in combination with the driving skids
15, 16, are designed such that the angle a made by the couplers 17,
18 is modified only by a minor amount upon motion of the work
spindle 12 into any position within the entire working range. This
has the effect that the two couplers 17, 18 rigidify each other,
which increases the rigidity of the coupler kinematics of the work
spindle 12 as compared to other known machine tools, accompanied
with simultaneous reduction of the moving mass. For this reason,
any machining forces generated on the edge of the tool 13 will lead
to some minor deflection of the work spindle 12. As compared to
other known machine tools, this machine tool, the basic design of
which is known from U.S. Pat. No. 6,328,510 B1 is able to carry out
heavy machining jobs with simultaneously increased precision.
Simultaneously, greater accelerations due to reduced mass help save
nonproductive times.
[0017] The skids 15, 16 are displaceably guided on guide rails 27,
28 which are disposed at a distance from each other in the z
direction on the inside of the side walls 2 and 3, respectively, to
which end they are provided with guide shoes 29, 30 that enclasp
the guide rails 27, 28. Combined with the guide shoes 29 and 30
that run on it, each guide rail 27, 28 constitutes a guide.
Provided between each guide rail 27, 28 that is mounted on a side
wall 2 and 3 and the corresponding guide shoes 29, 30, linear
motors 31, 32 are provided as drives. The respective primary part
33 of each linear motor 31, 32 is mounted on the side turned
towards the neighboring side wall 2 and 3 between the pairs of
guide shoes 29, 30. Current supply of the primary parts 33 takes
place via electric connectors 34 that are only roughly outlined.
The secondary part 35 of each linear motor 31 and 32 which is
allocated to each primary part 33 and formed by magnetic armatures
35a is provided on the respective side wall 2 and 3 between the
guide rails 27, 28, which are disposed by twos at a distance from
each other on the inside of the respective side wall 2 and 3. The
primary part 33 and the secondary part 35 can be cooled by means of
cooling devices 36, 37.
[0018] The position of each linear motor 31, 32 is detected by a
path measuring system 38, 39. The path measuring systems 38, 39 are
disposed between the respective linear motor 31, 32 and the guide
27, 29 and 28, 30, respectively, that is adjacent the working area
9. The ruler-type stationary portion 40 of each system 38, 39 is
mounted on the associated side wall 2, 3, whereas the movable
portion 41 in the form of a tracer is mounted on the respective
skid 15, 16.
[0019] The secondary parts 35, the guide rails 27, 28, and the
stationary portions 40 of the path measuring systems 38, 39 are
mounted by screws 42, 43, 44 on the inside, open towards the
working area 9, of the respective side wall 2 and 3, which provides
for ease of accessibility and assembly and disassembly. The same
applies to the primary parts 33, the guide shoes 29, 30 and the
movable portions 41 of the path measuring systems 38, 39. Arranging
the linear motors 31, 32 between the guides 27 to 30 results in a
guidance of the skids 15, 16 of high torsional rigidity.
Furthermore, the forces of attraction of the linear motor 31 and
32, respectively, can be transmitted directly to the associated
skid 15 and 16, with the effect of only minor deformation of the
skid 15 and 16. The rigid design of the skids 15, 16 as well as the
favorable arrangement of the linear motors 31, 32 and of the path
measuring systems 38, 39 work in favor of the control behavior of
the machine tools and thus of the quality of machining.
[0020] Simple assembly is feasible for example by the primary parts
33 first being mounted on the respective skid 15 and 16 and by the
skid 15, 16 then being placed on the respective guide rails 27, 28.
Afterwards, the skid 15 and 16 is moved into an upper or lower
extreme position and a part of the magnetic armatures 35a that form
the secondary part 35 are screwed on the free area of the inside of
the respective side wall 2, 3. Subsequently, the respective skid
15, 16 is moved into the other extreme position and then the other
part of the magnetic armatures 35a is fastened.
[0021] For equilibration of the skids 15, 16, equilibration means
45 are provided in the side wall 2 and 3 of the column 1
substantially consisting of a gas spring 46 in the form of a piston
cylinder unit, the piston rod 47 of which is mounted on a lower
bracket 48 of the respective skid 15, 16. The gas spring 46 exerts
an upward tensile force in the y direction on the respective skid,
compensating the weight of the respective skid 15 and 16 with all
the parts it carries. With the fact in mind that the couplers 17,
18 and the work spindle support 25, together with the work spindle
12, are movable also in the x direction, the weight that acts on
the respective skid 15 and 16 during operation of the machine
changes so that complete compensation of the weight forces does not
take place by way of the equilibration means 45, which is however
of no importance. In addition to serving for equilibration, the gas
springs 46 may be used for moving the skids 15 and 16 during
maintenance jobs by compressed-air supply and corresponding
triggering being employed when the power supply of the linear
motors 31, 32 has been switched off.
[0022] Further, a brake shoe 49 is disposed between the guide shoes
29, 30 that are allocated to a respective guide rail 27 and 28; it
is likewise fastened by screws to the respective skid 15, 16. The
brake shoes 49 are open during operation by compressed air; upon
interruption of the power supply of the linear motors 31, 32, the
brake shoes 49 are deaerated and close so that the skids 15, 16 are
held onto the guide rails 27, 28 as though by a mechanical locking
brake.
[0023] Allocated to the bottom 4 and the upper part 5, end-of
travel dampers 51, 52 are provided for each skid 15, 16, with
corresponding stops 53, 54 on the respective skid 15 and 16 being
allotted thereto. This helps ensure that these end-of-travel
dampers 51, 52 work when one of the skids 15, 16 moves beyond the
upper or lower maximum travel given by the control. Upon breakdown
of the control or any other failure, it is conceivable that the
distance of the two skids 15, 16 relative to each other in the
vertical y direction becomes to great, as a consequence of which
the work spindle 12 leaves the working range 26 in the horizontal x
direction, the work spindle support 25 hitting against a side wall
2 or 3 inclusive of the parts mounted thereon. For this to be
prevented, a distance limiter 55 is provided, which may for
instance be a pliable belt 56 the ends of which are held on the
underside of each skid 15, 16 by a presser plate 57 which is joined
to the skid 15, 16 by screws 58. This pliable belt 56 is designed
to have a rigidity such that, upon failure of the linear motors 31,
32, it will reduce or convert the kinetic energy of the entire
moving mass in the x-y plane--possibly cooperating with the
end-of-travel dampers 51, 52--without the work spindle support 25
or another moving part colliding with any mechanical boundary.
Energy conversion can be considered to be put into practice in
particular by flexible deformation of the belt 56, whereby the
energy is stored as potential energy. The pliable belt 56 may
consist of various materials. Preferably, use is made of a fabric
belt of polyamide as known from load suspension means in materials
handling technology. However these belts do not convert the entire
absorbed energy into heat; rather, backspringing will occur at the
end of such an emergency travel. The emergency travel is the travel
of the work spindle support 25. In the case of such an emergency,
the belt 56 experiences durable elongation and must be
replaced.
* * * * *